In rotating machines such as electric motors, or deflection electromagnets in accelerators, or the like, saddle type coils are typically used. Particularly when a high level of magnetic field intensity is required, superconductive technology is employed.
Meanwhile, in a tape-like superconductive wire such as an yttrium-based superconductive wire, it is difficult to bend the wire in the width direction. If the wire is forcibly bent in the width direction, a large distortion occurs in the superconductor, resulting in a deterioration in the superconductive properties.
Accordingly, in the case of a superconductive coil with a three-dimensional bent portion such as a saddle type coil, in order to reduce the distortion caused by the bending in the width direction, a method of tilting the superconductive wire in the bent portion is employed (e.g., Refer to Patent Documents 1, 2, and 3).
A difference between the length of one end portion of the tape-width direction at the bent portion and the length of the other end portion of the tape-width direction at the bent portion gives a bent distortion in the width direction. This method of tilting the superconductive wire in the bent portion is for decreasing the difference in the length between both of the longitudinal end portions in order to reduce the bent distortion in the width direction.